CN115468270A

CN115468270A - Apparatus, system, and method for gas leak detection

Info

Publication number: CN115468270A
Application number: CN202210502688.8A
Authority: CN
Inventors: 菲利普·福斯特; A·西洛里亚; 马丁·威利特
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2021-06-11
Filing date: 2022-05-10
Publication date: 2022-12-13
Also published as: US20220397297A1; EP4102147A1

Abstract

The invention provides an apparatus, system and method for gas leak detection. Methods, devices, and systems for monitoring gas leaks are disclosed herein. An example heating, ventilation and air conditioning (HVAC) may include: a sampling tube fluidly coupled to a first opening defined in the conduit; and a sensor assembly fluidly coupled to the sampling tube. The coupon is positioned outside the conduit and extends in the direction of gravity. The sensor assembly is configured to receive one or more gases having a greater density than ambient air and sense the one or more gases to generate a signal.

Description

Apparatus, system, and method for gas leak detection

Technical Field

The present disclosure relates generally to methods, systems, and associated sensor assemblies for monitoring gas leaks, and more particularly to sensor assemblies for monitoring and detecting refrigerant gas leaks.

Background

The refrigeration unit includes a refrigerant coil containing a flammable refrigerant. Leaks can be dangerous due to the flammability of the refrigerant, and therefore need to be detected before a sufficient amount of refrigerant leakage could cause a fire or the possibility of an explosion. Many of these identified problems have been addressed through efforts, wisdom, and innovation, including development solutions in embodiments of the present disclosure, many examples of which are described in detail herein.

The above illustrative summary, as well as other exemplary purposes and/or advantages of the present disclosure, and the manner of attaining them, is explained further in the following detailed description and the accompanying drawings.

Disclosure of Invention

According to various examples of the present disclosure, various example methods, apparatus, and systems may be provided for monitoring gas leaks.

In some examples, a heating, ventilation, and air conditioning (HVAC) system may be provided. In some examples, the HVAC may include: a sampling tube fluidly coupled to a first opening defined in the conduit; and a sensor assembly fluidly coupled to the sampling tube. In some examples, the coupon is positioned outside of the conduit and extends in the direction of gravity. In some examples, the sensor assembly is configured to receive one or more gases having a greater density than ambient air and to sense the one or more gases to generate a signal. In some examples, the sensor assembly includes a first opening configured to allow one or more gases to diffuse therethrough.

In some examples, the first opening includes a filter configured to screen out dust and moisture from the one or more gases reaching the sensor assembly.

In some examples, the HVAC may include a washpipe. In some examples, the irrigation tube includes a first end and a second end. In some examples, the flush tube is fluidly coupled to the sensor assembly at the second end. In some examples, the irrigation tube is fluidly coupled to the conduit at the first end. In some examples, the flush tube is configured to receive one or more gases including ambient air from the refrigeration unit.

In some examples, the second end is positioned downstream of the first opening. In some examples, the HVAC includes a drain pipe fluidly coupled to the sensor assembly. In some examples, the drain is configured to allow one or more gases to flow out of the sensor assembly. In some examples, the HVAC includes a blower disposed within the duct unit interior, the blower configured to be periodically activated to blow the ambient air into the washpipe.

In some examples, a sensor assembly may be provided. In some examples, the sensor assembly includes a chamber fluidly coupled to the sampling tube. In some examples, the chamber is configured to receive one or more gases from the sampling tube. In some examples, the chamber includes a second opening configured to allow the received one or more gases to flow out through the second opening; and a gas sensor disposed within the chamber, the gas sensor configured to sense the one or more gases to generate a signal.

In some examples, the sensor assembly may include a purge tube fluidly coupled to the chamber, the purge tube configured to facilitate a flow of the ambient air to the chamber to evacuate the one or more gases from the chamber, wherein the purge tube evacuates the one or more gases from the chamber and the gas sensor when the purge tube is configured to receive the one or more gases including ambient air from a conduit.

In some examples, the sensor assembly includes a drain fluidly coupled to the chamber. In some examples, the drain is configured to allow the one or more gases to escape therethrough when receiving ambient air from the flush tube.

In some examples, the sensor assembly includes a first opening of the conduit. In some examples, the first opening has a filter. In some examples, the filter is configured to screen out dust and moisture from the one or more gases reaching the chamber.

In some examples, the purge tube includes a plurality of heat exchange blades to reduce the temperature of the one or more gases reaching the chamber.

In some examples, the sensor assembly may include a blower configured to move fluid through the sensor assembly.

In some examples, a catheter unit may be provided. In some examples, the catheter unit includes a catheter having: a first opening along a direction of gravity; and a second opening complementary to the first opening and along the direction of fluid flow. In some examples, the first opening is fluidly coupled to a sampling tube positioned outside of the conduit. In some examples, the second opening is fluidly coupled to an irrigation tube positioned outside of the catheter.

In some examples, the first opening includes a filter configured to screen out dust and moisture from one or more gases passing therethrough.

In some examples, the one or more gases include a refrigerant.

In some examples, the second opening is fluidly coupled to the irrigation tube. In some examples, the flush tube includes a bend and faces the blower to facilitate flow of one or more gases, including ambient air.

In some examples, the duct unit may include a blower. In some examples, the blower may be configured to facilitate flow of one or more gases to the flush tube. In some examples, the blower may be configured to activate at periodic intervals.

Drawings

The description of the illustrative embodiments may be read in connection with the figures. It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the drawings presented herein, in which:

FIG. 1 illustrates an exemplary schematic diagram of a standard heating, ventilation and air conditioning unit (HVAC) system.

Fig. 2 shows an exemplary schematic view of a catheter unit according to one or more embodiments of the present disclosure.

Fig. 3 illustrates an exemplary schematic diagram of a sensor assembly according to an exemplary embodiment of the present disclosure.

Fig. 4 illustrates an exemplary partial schematic view of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure.

Fig. 5 illustrates an exemplary cross-sectional view of a sensor assembly according to an exemplary embodiment of the present disclosure.

Fig. 6 illustrates an exemplary block diagram of a control unit according to an embodiment of the present disclosure.

Fig. 7 illustrates an example flow diagram of a method for operating an HVAC used in accordance with an example embodiment of the present disclosure.

Fig. 8 shows an exemplary schematic view of a catheter unit according to another embodiment of the present disclosure.

Fig. 9 shows an exemplary schematic diagram of a sensor assembly according to an embodiment of the present disclosure.

Fig. 10 illustrates an exemplary cross-sectional view of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure.

Fig. 11 illustrates an exemplary fluid flow diagram within a sensor assembly according to an embodiment of the present disclosure.

Fig. 12 illustrates an example fluid flow diagram within a sensor assembly used in accordance with an example embodiment of the present disclosure.

Fig. 13 shows an exemplary schematic view of a catheter used in accordance with another exemplary embodiment of the present disclosure.

Figure 14 illustrates an example block diagram of an HVAC configured in accordance with an example embodiment of the present disclosure.

Fig. 15 shows a schematic view of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure.

Fig. 16 shows a schematic view of a sensor assembly used in accordance with an exemplary embodiment of the present disclosure.

Fig. 17 illustrates an exemplary flow diagram of a method for operating the sensor assembly of fig. 14 used in accordance with an exemplary embodiment of the present disclosure.

FIG. 18 is a graph illustrating voltage output of two oxygen sensors during a change in oxygen concentration level.

Fig. 19 is a graph showing test results using an exemplary embodiment of the present disclosure, in which butane is the target gas.

Fig. 20 is a block diagram of a sensor assembly with a flue configured in accordance with an exemplary embodiment of the present disclosure.

Fig. 21a illustrates an example block diagram of a closed flue sensor assembly configured in accordance with an example embodiment of the disclosure.

Fig. 21b illustrates an example block diagram of a sensor assembly configured in accordance with an example embodiment of the present disclosure, wherein the flue extends outside of the closed system. And is

Fig. 22 illustrates an example block diagram of a sensor assembly configured in accordance with an example embodiment of the present disclosure.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Detailed Description

Some embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the disclosure are shown. Indeed, these disclosures may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. The terminology used in this patent is not meant to be limiting, and the devices described herein or portions thereof may be attached or utilized in other orientations.

The phrases "in one embodiment," "according to one embodiment," "in some examples," and the like generally mean that a particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure, and may be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

The word "exemplary" is used herein to mean "serving as an example, instance, or illustration. Any specific implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other specific implementations.

If the specification states a component or feature "may", "can", "should", "will", "preferably", "possibly", "commonly", "optionally", "for example", "often", or "may" (or other such words) be included or having a characteristic, that particular component or feature is not necessarily included or having that characteristic. Such components or features may optionally be included in some embodiments, or may be excluded.

Various embodiments discussed herein allow for monitoring and detecting gas leaks during operation, such as in a heating, ventilation, and air conditioning (HVAC) unit. In some examples, such refrigerants include safety class A2L refrigerants such as, but not limited to, R-410A, R-1234yf, R-1234ze, R-32, R-454A, R-404A, R-454C, R-455A, R-447A, R-452B, R-454B, and the like. A2L refrigerant/refrigerant gas or gases are more commonly used in such refrigeration units due to lower Global Warming Potential (GWP) and therefore regulations have been enacted in various countries to monitor leaks to avoid hazardous conditions during use. Although A2L refrigerants generally have low toxicity and only slight flammability, a large leak can still create a hazardous situation. Thus, in some examples, monitoring and detection of such leaks is necessary for the refrigerant unit.

Generally, the vapor density of the A2L refrigerant is greater than ambient air. Thus, the refrigerant sinks by gravity to the lowest point of the refrigeration unit. Therefore, monitoring and detection of the gas at the lowest point (in the direction of gravity) of the refrigeration unit is required.

Various exemplary embodiments of the present disclosure allow for a simple and effective leak monitoring system. Additionally, the monitoring system may continuously receive output from the sensors to allow the monitoring system to provide self-test functionality to verify that the monitoring system is operational.

While various embodiments discuss refrigeration units, the various embodiments discussed herein may also be used for other types of gas leaks, such as heating, ventilation, and air conditioning (HVAC) applications using a closed loop cycle, flame suppression systems, and the like. For example, other such examples include, but are not limited to, inert gas leaks, natural gas leaks, propane gas leaks, butane gas leaks, carbon monoxide gas leaks, hydrocarbon gas leaks, and the like. Various embodiments discussed herein allow for detection of large-scale leaks. For example, the gas leaks at about 1% volume/volume or above about 1% volume/volume.

FIG. 1 is an exemplary schematic diagram of a standard heating, ventilation and air conditioning unit (HVAC) system 10. The HVAC system 10 is an exemplary embodiment that may include or be associated with any of a variety of computing or sensing devices. The HVAC system 10 includes a condenser unit 12 and an air handler or duct unit 14.

One of the condenser unit 12 and the duct unit 14 may include suitable logic and/or circuitry that may enable the condenser unit 12 to facilitate cooling and/or heating of ambient air (flowing through the HVAC system 10). For example, as shown in fig. 2, the condenser unit 12 may include a plurality of cooling/refrigeration conduits 16 that are fluidly coupled to a compressor (not shown). The compressor may flow one or more refrigerant gases through the plurality of cooling tubes. In some examples, a portion of the plurality of cooling tubes 16 may be positioned within the conduit unit 14. The duct unit 14 may be configured to facilitate a flow of ambient air over the portion of the plurality of cooling ducts positioned within the duct unit 14. This portion of the cooling duct may facilitate cooling/heating of the ambient air. The structure of the catheter unit 14 is further depicted in fig. 2.

Fig. 2 shows a schematic view of a catheter unit 14 according to one or more embodiments of the invention. The duct unit 14 includes a duct 20, a blower or fan 30, a control unit 40 and a sensor assembly 50. In some embodiments, control unit 40 is communicatively coupled to blower 30 and sensor assembly 50.

The conduit 20 has a conduit inlet 22 and a conduit outlet 24. The conduit inlet 22 is configured to receive ambient air from the environment. In some embodiments, the conduit inlet 22 may be fluidly coupled to additional conduits (not shown), wherein each additional conduit is configured to supply ambient air into the conduit 20. Additionally or alternatively, the duct inlet 22 may be fluidly coupled to other components of the HVAC system 10 that are configured to supply ambient air to the duct 20. In an exemplary embodiment, the duct outlet 24 may be configured to provide conditioned air to other components of the HVAC system 10. In some embodiments, the conduit 20 may be defined by one or more walls defining a perimeter of the conduit 20.

The duct 20 of fig. 2 includes at least a first wall 26 and a floor 28. The first wall 26 extends parallel to the vertical axis 21 of the duct unit 14. The vertical axis 21 is defined parallel to the gravitational force 18. In some embodiments, the floor 28 is coupled to the first wall 26 and extends perpendicular to the vertical axis 21.

A blower 30 may be positioned within the duct 20 to facilitate the flow of ambient air through the duct 20 and force the ambient air to flow over the plurality of cooling/refrigeration ducts 16. The blower 30 has a blower opening 32 through which ambient air is pushed, resulting in an air flow 34 through the conduit 20. In some embodiments, blower 30 may include suitable logic and/or circuitry (not shown) to control the speed and volume of airflow 34. The blower 30 may have a blower opening 32 that faces the first end 228 of the flush tube 170. The blower 30 may be configured to be periodically activated to blow ambient gas into the washpipe 170.

In this embodiment, the blower 30 flushes the sensor assembly 50 each time the blower 30 is operated. Each time the blower 30 is operated, the sensor assembly 50 is continuously flushed to remove gas from the system and the sensor assembly 50 is baseline to the same refrigerant gas level. This is to ensure that the sensor assembly 50 samples the same concentration of refrigerant gas as is located in the conduit 20.

In another embodiment, the blower 30 may be connected to the sensor assembly 50. In this embodiment, the blower 30 is configured to generate an airflow through the sensor assembly 50 to flush the sensor assembly 50. The blower 30 of this embodiment may be located within the conduit 20 and mechanically coupled to the sensor assembly 50 and mounted as part of the sensor assembly 50. In this embodiment, activation of blower 30 is initiated by a signal from control system 40.

In another embodiment, blower 30 may be connected to sensor assembly 50 and located outside of conduit 20. In this embodiment, the blower 30 may be mechanically coupled to the sensor assembly 50 and may be mounted as part of the sensor assembly 50. The blower 30 of this embodiment is configured to generate an airflow through the sensor assembly 50.

The control unit 40 may include suitable logic and/or circuitry communicatively coupled to the blower 30 and the sensor assembly 50. In some embodiments, the control unit 40 may be coupled to the condenser unit 12. The control unit 40 may be coupled to the HVAC system 10 and configured to control operation of the HVAC system 10. For example, the control unit 40 may be configured to activate/deactivate the blower 30, or otherwise control the blower 30, to adjust the speed and volume of the airflow 34 within the conduit 20. The control unit 40 may be implemented as an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA). In some embodiments, the control unit 40 may include electronic, electromechanical, and mechanical technologies. The structure and operation of the control unit 40 will be described later in conjunction with fig. 6.

In another embodiment, the control unit 40 is not configured to control the operation of the HVAC system. In this embodiment, the control unit 40 may be configured to control the airflow through the sensor assembly 50.

Sensor assembly 50 is coupled to conduit 20 through a floor opening 29 in floor 28. The sensor assembly 50 is located below the portion of the plurality of cooling tubes 16 positioned within the conduit 20. In some embodiments, the sensor assembly 50 may be located directly below the portion of the plurality of cooling tubes 16 positioned within the conduit 20. In other embodiments, the base plate 28 may include slots (not shown) or other structures that direct the flow of gas into the sensor assembly 50. In other embodiments, the sensor assembly 50 may include a structure, such as a slot or funnel, for placement within a conduit to direct a flow of gas into the sensor assembly 50.

Sensor assembly 50 may be coupled to control unit 40 and may be configured to provide a signal to control unit 40 when sensor assembly 50 detects a particular predefined gas. In alternative embodiments, the sensor assembly 50 may be coupled to the control unit 40 and may be configured to provide a signal to the control unit 40 when the sensor assembly 50 does not detect a particular predefined gas.

Accordingly, the control unit 40 may be configured to monitor the signals received from the sensor assembly 50. Based on the monitoring of the signal from the sensor assembly 50, the control unit 40 may be configured to activate/deactivate the blower 30 or adjust the speed and volume of the airflow 34 through the conduit 20 based on the signal from the sensor assembly 50. In another embodiment, the control unit 40 may be configured to automatically activate/deactivate the blower 30 without any intervention or association with signals from the sensor assembly 50.

Fig. 3 shows a schematic view of a sensor assembly 50 according to embodiments shown herein.

Fig. 4 illustrates a cross-sectional view of sensor assembly 50 as plane 80 cuts sensor assembly 50 according to one or more embodiments described herein. The sensor assembly 50 includes a first opening 52 and a second opening 54. The first opening 52 is coupled to a sampling tube 58. In the exemplary embodiment, the sampling tube 58 is received within a floor opening 29 in the floor 28 (as shown in FIG. 2). The sensor assembly 50 includes a first filter unit 60 positioned over the first opening 52 and a second filter unit 62 positioned over the second opening 54. In some examples, the first filter unit 60 may be configured to limit the ingress of dust particles and moisture into the sensor assembly 50.

The sensor assembly 50 defines a chamber 64 between the first opening 52 and the second opening 54. The chamber 64 is adjacent to a gas sensor 66. Gas sensor 66 is disposed adjacent to and connected to circuit 68. In some examples, the gas sensor 66 may be disposed within the chamber 64. In some examples, the gas sensor 66 is positioned along the first opening 52 or the sidewall 56 of the chamber 64. Gas sensor 66 may embody a plurality of gas concentration sensors configured to detect a concentration of one or more gaseous fluids. In various embodiments, the gas concentration sensor may be an electrochemical sensor configured to monitor the concentration of one or more refrigerant gases, as discussed below.

The sensor assembly 50 may include a connection port 70. The connection port 70 may be a USB or other standard electrical connector. The connection port 70 may be used to connect to the control unit 40 or one of the other devices for the data acquisition device.

Fig. 5 shows a fluid flow diagram within the sensor assembly 50. During operation, one or more refrigerant gases 70 pass through sampling tube 62 into chamber 64 to reach gas sensor 66. The gas sensor 66 detects the presence of one or more refrigerant gases 70. Due to the higher vapor density, the one or more refrigerant gases 70 may tend to move slowly within the sensor assembly 50 and then exit the second opening 54.

In some embodiments, the second filter 62 may be a check valve for restricting air from entering the gas sensor assembly from the ambient environment of the sensor assembly 50. The second filter 62 may include structure that restricts the outflow of one or more refrigerant gases to allow a concentration of one or more refrigerant gases to build up over time. In these embodiments, the second filter 62 may allow one or more refrigerant gases to be expelled from the sensor assembly 50 by the flow of ambient air, thereby creating a positive pressure created by activation of the blower 30.

In some examples, the scope of the present disclosure is not limited to a sensor assembly having a single sensor assembly or having a single gas sensor coupled to a conduit. In an exemplary embodiment, a plurality of sensor assemblies 50 may be coupled to the conduit 20 without departing from the scope of the present disclosure. In another exemplary embodiment, the sensor assembly 50 may include a plurality of gas sensors 62. Further, the scope of the present disclosure is not limited to sensing one or more refrigerant gases to determine leaks in a plurality of refrigeration coils. In an exemplary embodiment, the sensor assembly 50 may be configured to determine oxygen concentration to determine leakage of one or more refrigerant gases, as further described in fig. 14-22.

In various embodiments, as discussed below, the gas sensor 66 may be an electrochemical sensor configured to monitor the concentration of one or more refrigerant gases, oxygen, or other gases that will be depleted as one or more gaseous fluids accumulate in the sensor. For example, one or more of the gas concentration sensors may be a fuel cell liquid electrolyte electrochemical sensor. In various embodiments, the gas concentration sensor may employ multiple electrodes, such as a sensing electrode, a reference electrode, and a counter electrode. The sensor also includes an electrolyte disposed over at least a portion of each electrode to form an ion path. One or more leads may be coupled to electrodes on the sensing element by electrical conductors, such as wires. The leads may extend through the housing and be embedded within the housing. The sensor also includes a capillary/pathway that can be processed through the substrate to allow diffusion/transfer of gas to the sensing electrode and/or electrolyte. The electrodes allow various reactions to occur to allow a current or potential to develop in response to the presence of the target gas. The resulting signal may then allow the concentration of the target gas to be determined. Various sensors may be used in embodiments of the present disclosure, such as liquid electrolyte electrochemical sensors (e.g., consumable anode (battery) or fuel cell pumps), high temperature solid electrolyte electrochemical sensors (e.g., zirconia or other oxygen ion conductors) and/or fluorescence quenching sensors (e.g., ruthenium-based dyes), optical sensors, non-dispersive infrared (NDIR) sensors, optical sensors, thermal sensors, semiconductor sensors, and the like. Although the sensors discussed herein are referred to as gas concentration sensors, the sensing devices discussed herein may take the form of partial pressure sensors.

The circuitry 60 of the exemplary embodiment may also optionally include a communication interface, which may be any means such as a device or circuitry embodied in hardware or a combination of hardware and software that is configured to receive data from and/or transmit data to other electronic devices in communication with the sensor assembly, such as communication via Near Field Communication (NFC) or other distance-based techniques. Additionally or alternatively, the communication interface may be configured to communicate via cellular protocols or other wireless protocols, including global system for mobile communications (GSM), such as, but not limited to, long Term Evolution (LTE). In this regard, the communication interface may include, for example, an antenna (or multiple antennas) and support hardware and/or software for enabling communications with a wireless communication network. Additionally or alternatively, the communication interface may include circuitry to interact with the one or more antennas to cause signals to be transmitted via the one or more antennas or to process signal receptions received via the one or more antennas.

In various embodiments, at least a portion of the sensor assembly 50 may be disposed adjacent to portions of the plurality of cooling ducts 16 within the HVAC system 10. For example, at least the sensor assembly 50 (shown in FIG. 1) may be proximate to portions of the plurality of cooling ducts 16, and the circuitry 68 may be disposed elsewhere.

In various embodiments, the sensor assembly 50 may be placed in sufficient proximity such that a leak of gas (e.g., refrigerant) may cause a change in oxygen concentration. In some embodiments, the sensor assembly 50 may be disposed at a location proximate to a region of the portion of the plurality of cooling ducts 16 where leakage occurs more than at other locations. For example, gas leaks may occur more often at the connections between different pipes. In various embodiments, the sensor assembly 50 may be disposed within the HVAC system 10 or the like such that any gas leaks may reach the sensor assembly 50.

In passive conditions (no air flow through the sensor assembly 50), heavier than air gas flows through the openings in the base plate 29 and into the sampling tube 58 of the sensor assembly 50. Gases heavier than air collect in the chamber 64 near the gas sensor 66. This occurs whether the concentration in the sampling area subsequently changes due to leak stopping or remedial dilution, which would provide inaccurate sensor readings. It is therefore important to be able to flush the sensor assembly 50 without compromising the ability of the gas sensor to receive and respond to leaking gas.

Fig. 6 shows a block diagram 100 of the control unit 40 according to one or more embodiments described herein. The control unit 40 includes a processor 102, a memory device 104, an input/output (I/O) device interface unit 106, a flush control unit 108.

The processor 102 may be embodied as one or more microprocessors with one or more accompanying digital signal processors, one or more processors without an accompanying digital signal processor, one or more coprocessors, one or more multi-core processors, one or more controllers, processing circuitry, one or more computers, various other processing elements including integrated circuits such as, for example, an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA), or some combination thereof. Although shown in fig. 6 as a single processor, in one embodiment, the processor 102 may include multiple processors and signal processing modules. The multiple processors may be implemented on a single electronic device or may be distributed across multiple electronic devices that are collectively configured to function as circuitry for the HVAC system 10. The plurality of processors may be in operable communication with each other and may be collectively configured to perform one or more functions of the circuitry of the HVAC system 10 as described herein. In an example embodiment, the processor 102 may be configured to execute instructions stored in the memory device 104 or otherwise accessible to the processor 102. When executed by the processor 102, the instructions may cause the circuitry of the HVAC system 10 to perform one or more functions as described herein.

Whether the processor 102 is configured by hardware methods, firmware/software methods, or a combination thereof, the processor may include an entity capable of performing operations according to embodiments of the present disclosure while configured accordingly. Thus, for example, when the processor 102 is embodied as an ASIC, FPGA, or the like, the processor 102 may include specially configured hardware for performing one or more of the operations described herein. Alternatively, as another example, when the processor 102 is embodied as a runner of instructions (such as may be stored in the memory device 104), the instructions may specifically configure the processor 102 to perform one or more of the algorithms and operations described herein.

Thus, the processor 102 as used herein may refer to a programmable microprocessor, microcomputer, or multiple processor chip or chips that can be configured by software instructions (applications) to perform a variety of functions, including the functions of the various implementations described above. In some devices, multiple processors dedicated to wireless communication functions and one processor dedicated to running other applications may be provided. The software application may be stored in an internal memory before being accessed and loaded into the processor. The processor may include internal memory sufficient to store the application software instructions. In many devices, the internal memory may be volatile or non-volatile memory such as flash memory or a mixture of both. The memory may also be located internal to another computing resource (e.g., to enable computer-readable instructions to be downloaded over the internet or another wired or wireless connection).

The memory device 104 may comprise suitable logic, circuitry, and/or interfaces that may be adapted to store a set of instructions that may be executed by the processor 102 to perform predetermined operations. Some of the commonly known memory implementations include, but are not limited to, a hard disk, random access memory, cache memory, read Only Memory (ROM), erasable Programmable Read Only Memory (EPROM) and Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory, magnetic cassettes, magnetic tape, magnetic disk storage devices or other magnetic storage devices, compact disk read only memory (CD-ROM), digital versatile disk read only memory (DVD-ROM), optical disk, circuitry configured to store information, or some combination thereof. In an example embodiment, the memory device 104 may be integrated with the processor 102 on a single chip without departing from the scope of the present disclosure.

The I/O device interface unit 106 may comprise suitable logic and/or circuitry that may be configured to communicate in accordance with one or more device communication protocols such as, but not limited to, an I2C communication protocol, a Serial Peripheral Interface (SPI) communication protocol, a serial communication protocol, a Control Area Network (CAN) communication protocol, and 1-

The communication protocol communicates with one or more components of the HVAC system 10. In an exemplary embodiment, the I/O device interface unit 106 may be in communication with the sensor assembly 50 and the blower 30. Some examples of the I/O device interface unit 106 may include, but are not limited to, a Data Acquisition (DAQ) card, an electrical driver drive circuit, and the like.

The flush control unit 108 may include suitable logic and/or circuitry that may be configured to monitor signals received from the sensor assembly 50, as further described in fig. 7.

In an exemplary embodiment, the signal may be indicative of the concentration of gas accumulated within the sensor assembly 50. For example, the signal may be indicative of the concentration of one or more refrigerant gases accumulated within the sensor assembly 50. Based on the concentration of the gas within the sensor assembly 50, the flush control unit 108 may be configured to activate/deactivate the blower 30, as further described in fig. 7. The flush control unit 108 may be implemented as an ASIC or FPGA without departing from the scope of the present disclosure.

Referring additionally to fig. 7, which illustrates a flowchart 120 of a method for operating the HVAC system 10 in accordance with the embodiments shown herein, at step 122 the HVAC system 10 includes means, such as the control unit 40, the processor 102, and the flush control unit 108, for activating the blower 30 to generate the flow 34 of ambient air through the duct 20.

The plurality of cooling tubes 16 located within the conduit 20 and coupled to the condenser unit 12 are configured to change the temperature of the ambient air. In some examples, one or more refrigerant gases may leak into the conduit unit 14 due to leaks in the plurality of cooling tubes 16. Since the one or more refrigerant gases are heavier than ambient air, the one or more refrigerant gases may fall from the plurality of cooling tubes 16 and accumulate along the bottom plate 28 or the bottom of the conduit 20.

At step 124, the HVAC system 10 includes means for receiving signals from the sensor assembly 50, such as the control unit 40, the processor 102, and the flush control unit 108. The signal is indicative of the concentration of one or more refrigerant gases in the sensor assembly 50. In an exemplary embodiment, the processor 102 is configured to determine the concentration of the one or more refrigerant gases based on the received signals. In another exemplary embodiment, the sensor assembly 50 may be configured to generate a signal corresponding to the concentration of one or more refrigerant gases in the sensor assembly 50.

At step 126, the HVAC system 10 includes means, such as the control unit 40, the processor 102, and the flush control unit 108, for comparing the determined gas concentration to a predetermined gas threshold. In an exemplary embodiment, the predetermined gas threshold may correspond to a threshold above which the concentration of one or more refrigerant gases is determined to be dangerous/harmful. In an exemplary embodiment, the predetermined gas threshold may be predefined during the manufacture of the HVAC. If the flush control unit 108 determines that the concentration of the one or more refrigerant gases is less than the predetermined gas threshold, the flush control unit 108 may be configured to repeat step 124. However, if the flush control unit 108 determines that the concentration of the one or more refrigerant gases is greater than the predetermined gas threshold, the flush control unit 108 may be configured to generate a notification signal, as shown in step 128. The predetermined gas threshold may be a maximum threshold or a minimum threshold. The predetermined gas threshold may indicate the presence of one or more refrigerant gases or the absence of one or more non-refrigerant gases, such as oxygen.

At step 128, the HVAC system 10 includes means, such as the control unit 40, the processor 102, and the flush control unit 108, for generating a notification signal that the gas threshold exceeds the threshold. In an exemplary embodiment, the notification may be transmitted to a user/operator of the HVAC to indicate that one or more refrigerant gases are leaking.

At step 130, the HVAC system 10 includes means for activating the blower 30, such as the control unit 40, the processor 102, and the flush control unit 108. The blower 30 is set to run for a predetermined amount of time. Once the blower is activated, the sensor assembly 50 will receive ambient air from the conduit 20 to flush or remove one or more refrigerant gases leaking from the sensor assembly 50. The ambient air may comprise a mixture of leaked refrigerant gas or gases and air, or simply ambient air present within conduit 20.

After blower 30 is activated for a predetermined amount of time, step 124 will be repeated. The controller 40 may be programmed to compare one or more signals from the sensor assembly 50 over a predetermined time range and provide an alert notification that the HVAC system 10 requires maintenance. Controller 40 provides an alarm of the presence of refrigerant gas and triggers one or more signals to initiate a precautionary measure to reduce the likelihood of the accumulation of a hazardous gas mixture within conduit 20.

In some embodiments, the alarm notification signal includes one of location information, gas concentration information, and sensor assembly fault information. In some embodiments, the alert notification signal may include one of an audible signal and a visual signal. In some embodiments, the alarm notification signal may adjust the blower 30 to prevent the accumulation of one or more refrigerant gases within the HVAC system 10.

During normal operation of the HVAC system 10, activation/operation of the blower 30 provides periodic cleaning of the sensor assembly 50 by forcing ambient air through the sensor assembly 50. This periodic cleaning of the sensor assembly 50 prevents the sensor assembly from being poisoned by continuously flushing ambient air past the sensor assembly and removing one or more refrigerant gases that may have leaked within the HVAC system 10. In addition, this operation also reduces the likelihood of false positives due to the continued presence of one or more refrigerant gases.

Fig. 8 shows a schematic view of a catheter unit 14 according to one or more embodiments of the invention. The conduit unit 14 of fig. 8 includes the conduit 20, blower 30 and control unit 40 shown in fig. 2, and a sensor assembly 150.

The sensor assembly 150 includes a sampling tube 158 and a flush tube 170. The sensor assembly 150 is fluidly coupled to the conduit 20 by both the sampling tube 158 and the flush tube 170. Sampling tube 158 is fluidly coupled to conduit 20 through floor opening 29 in floor 28. The flush tube 170 is fluidly coupled to the conduit 20 through the wall opening 27 in the first wall 26. In an exemplary embodiment, at least a portion of the irrigation tube 170 may be positioned outside of the catheter 20.

In an exemplary embodiment, the flush tube 170 may include a first end portion 172, a second end portion 174, and an intermediate portion 176. A first end 172 of the flush tube 170 is fluidly coupled to a second opening of the sensor assembly 150. The second end 174 of the irrigation tube 170 may include an interior portion 180 positioned inside the conduit 20 and configured to collect the flow 34 of ambient air. In some examples, the second end 174 of the rinse tube 170 may define a bend 178 that causes the second end 174 of the rinse tube 170 to face the direction of the airflow 34.

In some embodiments, the second end 174 of the flush tube 170 may be positioned to face the blower opening 32 of the blower 30. The blower 30 may be configured to be periodically activated to blow ambient gas into the washpipe 170.

Fig. 9 shows a schematic view of a sensor assembly 150 according to embodiments shown herein. The sensor assembly 150 includes a first opening 152 and a second opening 154. The first opening 152 is coupled to the sampling tube 58 and the second opening 154 is coupled to the second end 174 of the flush tube 170.

In an exemplary embodiment, the coupon includes a plurality of capillaries to allow diffusion of one or more gases therethrough.

Fig. 10 illustrates a cross-sectional view of the sensor assembly 150 as the plane 180 cuts the sensor assembly 150 according to one or more embodiments illustrated herein. The sensor assembly 150 includes a first filter unit 160, a gas sensor 166, a circuit 168, and may be a second filter unit (not shown). Gas sensor 166 is disposed on top of circuit 168. The gas sensor 166 is exposed to the flush tube 170 and the sampling tube 158. The gas sensor 166 can be disposed in a direction perpendicular to the direction of the one or more refrigerant gases entering the gas sensor 166. In an exemplary embodiment, the gas sensor 166 may be disposed in a direction parallel to the outflow direction of the one or more refrigerant gases. In an exemplary embodiment, the first opening 152 includes a first filter unit 160, and the second opening 54 may include a second filter unit (not shown), the first and second filter units being configured to screen out dust and moisture from the one or more gases reaching the sensor assembly. In some examples, the sensor assembly 150 may define a chamber 164, with the flush tube 170 and the sampling tube 158 fluidly coupled to the chamber 164. In some examples, a gas sensor 166 is located within the chamber 164.

Fig. 11 illustrates a fluid flow diagram within a sensor assembly 150 according to embodiments shown herein. During operation, when blower 30 is not activated, one or more refrigerant gases pass through sampling tube 158 into chamber 164 and to gas sensor 166, and gas sensor 166 detects the presence of the one or more refrigerant gases. Due to the higher vapor density, one or more refrigerant gases may tend to accumulate within the sensor assembly 150.

Fig. 12 shows a fluid flow diagram within a sensor assembly 150 according to embodiments shown herein. During operation, when the blower 30 is actuated, the flush tube 170 will receive ambient air from the conduit 20, which will move towards the chamber 164 under the influence of the blower. Due to the pressure of the ambient air in the flush tube 170, the flush tube 170 facilitates the flow of ambient air to the chamber to evacuate the one or more refrigerant gases from the chamber. In addition, the pressure of the ambient air in the flush tube 170 also evacuates one or more refrigerant gases from the chamber 164 and the gas sensor 504. This movement of the mixture of ambient air and residual refrigerant gas or gases will be well below the threshold and the sensor assembly may be unaffected by the residual refrigerant gas or gases. Thus, the potential for poisoning of the gas sensor 166 is reduced and/or variations in sensor reading inaccuracies are reduced.

In some examples, the scope of the present disclosure is not limited to the positioning of the irrigation tube 170 relative to the catheter 20. In exemplary embodiments, the positioning of the irrigation tube 170 may vary based on the orientation of the catheter 20 without departing from the scope of the present disclosure. One such example is shown in fig. 13. In the illustrated embodiment of fig. 13, both the sampling tube 158 and the flush tube 170 are fluidly coupled to the floor of the conduit 20.

In another embodiment, the flush tube 170 may include heat exchange fins to cool the ambient air entering the sensor assembly 50.

It has been demonstrated that refrigerant gas can also leak through the walls and under the air handler unit. Another advantage is that the flushing action will remove refrigerant from the flue and the sensor, which will also distribute fresh air around the outlet of the sensor. Thus, the flushing action dilutes the concentration of leaking refrigerant collected in this area as a safety mitigation factor. This is shown as the outlet on the right side of the sensor housing in fig. 13. In some embodiments, the irrigation tube 170 may extend substantially parallel to a horizontal axis 190 of the catheter 20. This advantage applies to any HVAC system that has an enclosed space below the leak where gas can collect, concentrate over time, and cause explosion or fire problems.

In some examples, the scope of the present disclosure is not limited to coupling one sensor assembly to a catheter. In an exemplary embodiment, a plurality of sensor assemblies may be coupled to the conduit 20 without departing from the scope of the present disclosure. Further, the scope of the present disclosure is not limited to sensing one or more refrigerant gases to determine leaks in a plurality of refrigeration coils. In an exemplary embodiment, the sensor assembly 150 may be configured to determine oxygen concentration to determine leakage of one or more refrigerant gases, as further described in fig. 14-22.

Figure 14 illustrates an HVAC 300 according to various embodiments of the present disclosure. As shown, the HVAC 300 may include one or more closed loop gas (e.g., refrigerant) coils 310 and a sensor assembly 150. In various embodiments, at least a portion of the sensor assembly 150 may be disposed adjacent a given closed loop gas coil 310 within the HVAC 300. For example, at least the sensor assembly 150 (shown in fig. 1) may be proximate to the closed loop gas coil 310, and the circuitry may be disposed elsewhere.

In various embodiments, the sensor assembly 150 may be placed in sufficient proximity such that a leak of gas (e.g., refrigerant) may cause a change in oxygen concentration. In some embodiments, the sensor assembly 150 may be disposed at a location near the area of the closed loop gas coil 310 where more leakage occurs than at other locations. For example, gas leaks may occur more often at the connections between different pipes. In various embodiments, the sensor assembly 150 may be provided with the HVAC 300 or the like such that any gas leaks may reach the sensor assembly 150.

Fig. 15 is an exemplary configuration of a sensor assembly 500 according to another exemplary embodiment. As shown, a primary sensing device 520 and a reference sensing device 522 may be disposed within the sensor assembly 500. In various embodiments, the sensor assembly 500 may be oriented such that the coil surface 510 is proximate to the closed-loop gas coil 310 and, in the event of such a leak, a gas (e.g., refrigerant) leak 515. Thus, the main sensing device 520 and the reference sensing device 522 may be disposed at a common location provided that the reference sensing device is exposed to ambient air by way of the flue extension. In some embodiments, there may be a performance tradeoff between the location of the leak, gas movement, sensor location, sensitivity, and response time of the sensing device. The response time is defined as the time from no load response to a step change in load of the sensor.

In some embodiments, the sensor assembly 500 may include a single sensor to allow the sensor to be located away from the gas leak 515. In some embodiments, the sensor assembly 500 may include a single NDIR sensor.

In various embodiments, any gas leak 515 may reach the primary sensing device 520 before the reference sensing device 522. The primary sensing device 520 and the reference sensing device 522 are configured to determine the presence of one or more target gases (e.g., oxygen, carbon dioxide, refrigerant, or another gas). Thus, the first oxygen concentration level reading captured by the primary sensing device 520 may change due to a gas leak (e.g., the oxygen concentration may decrease) before the second oxygen concentration level reading captured by the reference sensing device 522 changes. Thus, in the event of a leak, the first oxygen concentration level reading may decrease faster than the second oxygen concentration level reading.

In some embodiments, the reference sensing device 522 may also be oriented differently from the primary sensing device 520 such that gas flowing from potential leak sites is inhibited from entering the reference sensing device 522 and not inhibited from entering the primary sensing device 520 (e.g., as shown by the arrows in fig. 15, the target gas may flow directly into the primary sensing device 520, but may have to travel around the circuit 530 and flue extension to enter the reference sensing device 522). Thus, the temporal effect of the airflow can be more clearly shown by the output of each sensing device. In some embodiments, a potential leak site may be defined as an area susceptible to a leak. For example, in a refrigeration unit, potential leak locations may include raised joints, connections between pipes, areas under mechanical and/or thermal stress, and the like. In various implementations, the location of the potential leak may be determined via application-specific testing.

In some embodiments, the reference sensing apparatus 522 may be exposed to the ambient environment, such as ambient air outside of the sensor assembly 500, via a flue extension coupled with the reference sensing apparatus 522. In this regard, the reference sensing device 522 may not receive any target gas during a leak condition. In such cases, the reference sensing device 522 may be located in an area having similar environmental conditions as the location of the primary sensing device 520. Although fig. 15 shows only a single primary sensing device 520 and a single reference sensing device 522, various embodiments may use more than two sensing devices disposed on a single PCB and at the same location (i.e., not spaced apart).

In various embodiments, at least a portion of the circuit 530 may be disposed within the sensor assembly 500. As shown, the primary sensing device 520 and/or the reference sensing device 522 may be connected to the circuit 530 via pins on the sensing device configured to engage with a socket on the circuit 530. Various embodiments may employ different connection methods, such as pogo pins configured on the circuit 530 and pads on the sensing device. Various implementations discussed herein may have any number of different standard electrical interconnects between the sensing device and the circuitry 530. In some embodiments, the master sensing device 520 and/or the reference sensing device 522 may be equipped with short range communication capabilities to allow the sensing devices to communicate remotely with the circuit 530. In various embodiments, circuitry 530 may be configured to receive oxygen concentration level readings from primary sensing device 520 and reference sensing device 522. In some implementations, the circuit 530 may store one or more of the oxygen concentration level readings such that the oxygen concentration level readings may be monitored over time (e.g., over time, the first oxygen concentration level reading and the second oxygen concentration level reading may be different due to a leak). In some embodiments, the time series data may be used to determine a leak condition. In various embodiments, the monitoring may be continuous. Alternatively, monitoring may be based on the intervals of gas leak application (e.g., some gas leaks may be less dangerous, and intermittent monitoring may save costs).

Fig. 16 is another exemplary configuration of a sensor assembly 500 according to an exemplary embodiment. As shown, the primary sensing device 520 and the reference sensor assembly 522 may be disposed within the same sensor assembly 500. As shown, the primary sensing device 520 and the reference sensing device 522 may be disposed at the same location in a gas leak environment.

In some embodiments, the reference sensing device 522 may be equipped with a filter 524 configured to remove one or more target gases (e.g., refrigerants) from the gas entering the reference sensing device 522. In some embodiments, filter 524 may be configured to absorb one or more target gases (e.g., one or more refrigerant gases) therethrough. For example, the filter 524 may be an absorber. In some embodiments, a filter 524 may be positioned between closed-loop gas coil 310 and reference sensing equipment 522 such that any combination of gases reaching the reference sensing equipment has passed through filter 524 (e.g., removing some or all of the one or more refrigerant gases).

In various embodiments, the filter 524 may be various types of activated carbon. In some such embodiments, the activated carbon may be impregnated with other chemicals, depending on the substance to be absorbed. In some embodiments, molecular sieves, zeolites, and/or other well known filter series may be used. In some embodiments, the target gas may determine the design of filter 524 (e.g., sofnocarb powder may be used in cases where butane is the target gas). In some embodiments, the filter 524 may be designed to permanently absorb the target gas or slow its passage through the reference sensing device such that a time difference in response occurs compared to the primary sensing device.

In some embodiments, the primary sensing device 520 and the reference sensing device 522 may be a single sensor having multiple gas inlets. For example, a single sensor may have a main sensing device gas inlet without filter 524 and a reference sensing device gas inlet that may have filter 524. In such embodiments, the sensing device may have a mechanical switch configured to switch access to the sensing electrode from the primary sensing device gas inlet to the reference sensing device gas inlet during operation. In such implementations, various pumping devices may be used to move gas from the gas inlet to the sensing electrode. During operation, the mechanical switch may switch between the primary sensing device gas inlet and the reference sensing device gas inlet, and the difference between the first oxygen level reading and the second oxygen level reading from the primary sensing device gas inlet may be compared with the dual sensing device system as described herein.

In some embodiments, when gas (e.g., refrigerant) leaks, the first oxygen concentration level reading of the primary sensing device 520 may begin to decrease while the second oxygen concentration level reading of the reference sensing device 522 remains substantially constant (or at least decreases more slowly). In some cases where the gas leak is sufficiently large, the filter 524 may be overloaded (e.g., fully saturated) at a particular point such that the second oxygen concentration level reading of the reference sensing device 522 may begin to decrease in unison with a sensing device without a filter. In such embodiments, a time lag between a decrease in the first oxygen concentration level and a decrease in the second oxygen concentration level may indicate that a gas leak has occurred. In addition, various other information may be determined via various outputs of the sensing device.

In various embodiments, at least a portion of the circuit 530 may be disposed within the sensor assembly 500 as a primary sensing device 520 and a reference sensing device 522. As shown, the primary sensing device 520 and/or the reference sensing device 522 may be connected to the circuit 530 via pins on the sensing device configured to engage with a socket on the circuit 530. Various embodiments may employ different connection methods, such as pogo pins configured on the circuit 530 and pads on the sensing device. Various implementations discussed herein may have any number of different standard electrical interconnects between the sensing device and the circuitry 530. In some embodiments, the primary sensing device 520 and/or the reference sensing device 522 may be equipped with short range communication capabilities to allow the sensing devices to communicate remotely with the circuit 530. In various embodiments, circuitry 530 may be configured to receive oxygen concentration level readings from primary sensing device 520 and reference sensing device 522. In some implementations, the circuit 530 may store one or more of the oxygen concentration level readings such that the oxygen concentration level readings may be monitored over time (e.g., over time, the first oxygen concentration level reading and the second oxygen concentration level reading may be different due to a leak). In various embodiments, the monitoring may be continuous. Alternatively, monitoring may be based on the intervals of gas leak application (e.g., some gas leaks may be less dangerous, and intermittent monitoring may save costs).

Referring now to fig. 17, an exemplary embodiment of the present disclosure includes a flow chart 600 for monitoring and detecting a gas (e.g., refrigerant) leak by the circuit 530, the processor 532, the sensing assembly 24, and the like. While various embodiments of the sensing assembly may include at least one processor 532, various embodiments of the sensing assembly may be analog systems such that the main sensing device 20 and the reference sensing device 22 may communicate with differential amplifiers and/or ratio amplifiers and use comparators to determine a leak condition. Thus, the operations of fig. 17 may be performed by a simulation system.

Referring now to block 610 of fig. 17, sensing assembly 500 (such as circuit 530, processor 532, etc.) may include means for receiving a first oxygen concentration level reading for a given area. In various implementations, as described above, the first oxygen concentration level reading may be captured by the primary sensing device 520. | A | A | A In various embodiments, the first oxygen concentration level reading may be affected by environmental conditions such as temperature, and the like. Additionally, in some embodiments, the first oxygen concentration level reading may be affected by the introduction of new gas (e.g., such as a gas leak that results in a decrease in oxygen concentration).

Referring now to block 620 of fig. 17, sensing assembly 500 (such as circuit 530, processor 532, etc.) may include means for receiving a second oxygen concentration level reading for a given area. In various implementations, as described above, the first oxygen concentration level reading may be captured by the reference sensing device 522. In various implementations, the reference sensing apparatus 522 may be positioned at similar environmental conditions such that the effect of the environmental conditions on the second oxygen concentration level reading may be similar to or the same as the effect of the environmental conditions on the first oxygen concentration level reading.

However, in various embodiments, the reference sensing device 522 may be configured such that the effect of the gas leak 515 on the second oxygen concentration level reading from the reference sensing device 522 may be different than the effect on the first oxygen concentration level reading from the primary sensing device 520. For example, where the reference sensing apparatus 522 is coupled with a flue, the flue does not allow leakage gas to pass through to the reference sensing apparatus. The second oxygen concentration level reading may begin to decrease after the first oxygen concentration level reading begins to decrease for a period of time, as gas (e.g., refrigerant) may take longer to reach the reference sensing device 522. Alternatively, where the reference sensing apparatus 522 is equipped with a filter 524 (e.g., fig. 16) or a flue, the second oxygen concentration level may not be reduced by gas leakage, whereas the first oxygen concentration level may be reduced by the gas leakage.

Referring now to block 630 of fig. 5, sensing assembly 500 (such as circuit 530, processor 532, etc.) may include means for comparing the first oxygen concentration level reading and the second oxygen concentration level reading. In various embodiments, the difference between the first oxygen concentration level reading and the second oxygen concentration level reading may be correlated to an amount of gas leak. In some embodiments, the comparison may be made at a given time (e.g., where the primary sensing device 520 has a lower oxygen concentration level reading than the reference sensing device 522). In some embodiments, the first oxygen concentration level reading and the second oxygen concentration level reading may be monitored over time such that a change in the first oxygen concentration level reading and the second oxygen concentration level reading may indicate that a gas leak has occurred.

In an exemplary analog embodiment, the main sensing device 520 and the reference sensing device 522 may measure output currents that are converted to voltages, and the respective output voltages may be amplified to eliminate any noise. Thus, the voltages may be compared using a differential or ratio. In such analog implementations, a comparator may be used to determine that a leak has occurred.

Referring now to block 640 of fig. 17, sensing assembly 500 (such as circuit 530, processor 532, etc.) may include means for causing transmission of a signal that a gas (e.g., refrigerant) leak occurred if a difference in the first oxygen concentration level reading and the second oxygen concentration level reading is greater than a threshold difference.

In various embodiments, a potential gas leak may be determined based on a comparison of the first oxygen concentration level reading and the second oxygen concentration level reading. In some embodiments, the amount of target gas (e.g., refrigerant) allowed to leak may be based on the flammability of the gas. Thus, the threshold difference may be lower than the flammability level of the target gas. For example, where the flammability level is 10%, the threshold difference may be 1%. For example, a 1% change in oxygen concentration (e.g., from 20.9% oxygen concentration to 20.7% oxygen concentration) may indicate a 1% leaking gas (e.g., refrigerant) concentration. In various embodiments, the difference between the first oxygen concentration level reading and the second oxygen concentration level reading may correlate to a change in oxygen concentration (e.g., the primary sensing device 20 and the reference sensing device 22 may be configured such that only introduction of the target gas (e.g., a gas leak) may result in the first oxygen concentration level reading and the second oxygen concentration level reading being significantly different). In various embodiments, the threshold difference may be between about 5% and 10% of the volume of the oxygen concentration level.

Fig. 18 is a graph showing similar oxygen concentration readings for two sensors (such as the oxygen sensor used in various embodiments herein) during changes in oxygen levels in air. As shown, two sensors being exposed to the same air show nearly identical readings and therefore can be relied upon to show significant changes in oxygen levels. The S2/S1 line shown is the ratio of sensor 2 readings to sensor 1 readings. As shown, the ratio is about 1, and thus any change in one of the sensor readings (e.g., where a gas leak occurs and the primary sensing device 520 experiences a reduction in oxygen before the reference sensing device 522) may be represented by a change in the ratio from about 1.

Fig. 19 shows the output of a sensor assembly (similar to that shown in fig. 16) in which a reference sensing device 522 is equipped with a stack and a filter 524. In the graph shown in fig. 19, the target gas is butane. As shown, the target gas is intermittently introduced into the sensor assembly, and each time the target gas is introduced, the main sensing device 520 experiences a spike (e.g., spikes 700A-700D) above the nominal voltage, while the voltage of the reference sensing device 522 remains substantially constant because the flue does not allow gas to pass therethrough or the filter absorbs butane. In the illustrated example, the difference is used to illustrate the case where leakage occurs and is shown as spikes 710A-710D.

FIG. 20 shows a block diagram of a sensor assembly similar to that shown in FIG. 16, except that a flue 800 is introduced that fits on one side of the reference sensing device 522. The chimney 800 enables the reference sensing device to be exposed to fresh air and away from a leaking environment 810 or area with leaking gas. On the other hand, the primary sensing device 520 is exposed to A2L gas leak of a severe nature. In this regard, a differential signal may be calculated based on the exposure of the leaking gas to the primary sensing device 520 and the exposure of the ambient air to the reference sensing device 522. To this end, the chimney 800 allows ambient air to diffuse or pass through and keeps the reference sensing device 522 away from leaking gases. In this regard, the efficiency of gas detection may be significantly enhanced based on the detection of changes in gas concentration in the working environment.

In an exemplary embodiment, the primary sensing device 520 and the reference sensing device 522 are co-located to detect A2L gas leak in an AC system. The differential sensor system has long life, self-calibration capability and high reliability. The sensor is programmed to detect the gas concentration after a predetermined time and to make a comparison based on the detected concentration. In this regard, the gas detection system recalibrates the threshold based on changes in ambient air (or oxygen) concentration. Furthermore, the system is highly reliable because both the primary sensing device 520 and the reference sensing device 522 are co-located, thereby exposing them to the same environmental variables, such as temperature, pressure, humidity, with different gas exposures. Thus, the detector system detects small changes in gas concentration described by the differential signal.

In another embodiment, two oxygen sensors are used to measure the decrease in oxygen concentration due to A2L gas leak. In the absence of a leak, both sensors are exposed to ambient air, producing a zero differential signal. However, to detect an A2L leak in the environment, the primary sensing device 520 is exposed to an area with leaking gas in order to detect a change in oxygen concentration. At the same time, a reference sensing device 522 fitted with a stack 800 detects the concentration of oxygen present in the ambient air. In this regard, each time the primary sensing device 520 detects a change in oxygen concentration, it compares it to the oxygen concentration in the ambient air. The control circuit receives signals from the primary sensing device 520 and the reference sensing device 522 and compares the signals to determine a differential signal. This differential signal is thus indicative of the change in oxygen concentration, and in other words the concentration of A2L gas in the environment. For example, a 1% change in oxygen concentration (e.g., from 20.9% oxygen concentration to 20.7% oxygen concentration) may indicate that the gas detection system may accurately detect a 1% leaking gas (e.g., refrigerant) concentration.

In another exemplary embodiment, the chimney 800 includes a filter (not shown) mounted at an inlet of the chimney 800 for preventing A2L from passing through the chimney. This results in an increase in sensitivity as the reference sensing device 522 detects the concentration of ambient air after filtering the A2L of gas.

In another exemplary embodiment, the gas detector system includes dual oxygen sensors, both configured to operate in an AC system. Sensor 1 is a primary sensing device 520 that detects depletion of oxygen by exposure to one or more refrigerant gases (e.g., A2L). Furthermore, the sensor 2 is equipped with a reference sensing device 522 that extends to the flue 800 of clean air (the time of absence of one or more refrigerant gases is approximately >10 minutes). The two sensors work together to generate a steady state differential signal.

In another exemplary embodiment, the design of the gas detector system is not affected by potential false positives due to temperature, pressure, and humidity variations. Unlike conventional dual oxygen sensor systems, the gas detector of the present invention does not trigger false alarms. Conventional oxygen sensors are operable to detect the concentration of oxygen in an environment and trigger an alarm when the detected concentration level exceeds a predetermined level without calculating the relative oxygen concentration. The relative oxygen concentration is calculated by comparing the sensed oxygen concentration to a reference threshold. The reference threshold is calibrated based on the ambient oxygen concentration at that time.

In another exemplary embodiment, the recalibration of the predetermined threshold is referred to as O ₂ Continuous self-test reading of the levels. In this regard, any heavy gas-containing substances are detectedWhat type of O ₂ And diluting to make the system suitable for different gases.

In another exemplary embodiment, two sensors are located close to each other, resulting in a compact design, thereby allowing the reference sensing device to be co-located with all electrical devices, thereby minimizing unit size and maximizing compensation performance. By having a compact configuration, errors or losses due to electrical losses are minimized, which results in a highly accurate and sensitive signal output.

In another exemplary embodiment, when the leak rate is high, the dual sensors are positioned at the bottom of the cabinet and a leak occurs at the top of the flue. The flue has a cylindrical shape with a cross-section having an inner diameter of about 0.625 inches (0.0158 m) and a height of about 6 inches (0.152 m). The reference sensing device 522 is exposed to the air at the top of the cabinet. The differential output is the difference between the main sensing device 520 and the reference sensing device 522 with the stack 800.

In another exemplary embodiment, the reference sensing device 522 may compensate for temperature, pressure, and humidity variations. One advantage is that other ambient gases (such as CO) can be compensated ₂ ) Any effect on the sensor to provide a more accurate reading. This is particularly useful in the case of oxygen sensors, but it is also applicable to other sensor technologies and interferences.

Further, the design of the chimney 800 is generic from a system design perspective. In this regard, flues 800 of different heights and different diameters may be used without interrupting the mean free path of the target gas.

In another exemplary embodiment, the flue is a passive element and can be easily integrated into existing systems of reference sensors. Furthermore, no pump is associated with the sensing system to push ambient air into the reference sensing device 522.

In another exemplary embodiment, the gas collection system has multiple chimneys leading to the sensor from various locations. Multiple chimneys enable multiple sensing locations within the air handler unit, providing a safety factor for HVAC manufacturers to ensure that leaked gas is not affected by the sensor locations when detected.

Fig. 21a is a block diagram of a flue 900 enclosed sensor assembly configured in accordance with an exemplary embodiment of the present disclosure. In this regard, the sensor system is placed within the furnace proximate to the metering device. The primary sensing apparatus 520 is exposed to conditions within a furnace or other enclosed area 902 and is modified with reference to the sensing apparatus using a flue 900 that may extend away from potential leakage sources. In this way, the flue 900 may be adjusted at a maximum height within the furnace, or may be extended out of containment of the furnace, as shown in fig. 21 b.

Referring to FIG. 21b, a block diagram of a sensor assembly is disclosed wherein flue 904 extends outside of closure system 906. In both configurations of fig. 21a and 21b, a flue 904 extending away from the area having leaked gas is configured to provide ambient air to the reference sensing device 522.

Fig. 22 is a block diagram of a sensing assembly configured in accordance with an example embodiment of the present disclosure. As shown in fig. 22, to determine oxygen concentration, one end of the stack 910 is coupled with the primary sensing device 520 and the second end reaches the gas leak environment. In this regard, the gas detector may detect a gas leak by exposing the primary sensing device 520 to the leaking environment via the flue 910, and the reference sensing device is adapted to be exposed to ambient air. In an exemplary embodiment, the flue may have any shape or size as desired, and the flue 910 is sized such that it allows the gas to freely diffuse or pass through without obstructing the mean free path of the gas. In this regard, the gas detector may be placed outside of the cabinet, furnace or vessel without affecting the sensing quality of the gas detector. This arrangement helps to extend the lifetime of the sensor and improve sensitivity due to the arrangement of the main and reference sensing devices on the Printed Circuit Board (PCB).

In another exemplary embodiment, the signal sensor is modified using a flue and is exposed to conditions inside the furnace by extending the flue to a location where one or more refrigerant gases leak in the vessel or furnace. For this reason, the reference sensor is open to conditions outside the furnace containment and is not affected by refrigerant leaks.

In another exemplary embodiment of the present invention, by placing the main sensing device and the reference sensing device close to each other, signal delays due to signal loss in the electronic circuit or transmission can be eliminated to a greater extent. Thus, with this structural arrangement, the signal-to-noise ratio can be improved compared to conventional differential sensors, thereby improving the response time. In this manner, the sensitivity of the gas detector can be increased by several times by minimizing the delay time due to structural constraints (such as the relative placement of the primary and reference sensing devices) or due to transmission circuitry or electronic circuitry.

Further, according to some exemplary embodiments, a sensor assembly for determining a composition of one or more gases includes: a primary sensing device and a reference sensing device located in proximity to the primary sensing device; a flue coupled with the reference sensing device at one end of the reference sensing device, wherein the reference sensing device is configured to determine a first oxygen concentration level of the given area via the flue, wherein the primary sensing device is configured to determine a second oxygen concentration level of the given area.

According to some exemplary embodiments described herein, a control circuit (which is electrically coupled with a primary sensing device and a reference sensing device) is configured to: receiving the determined first and second oxygen concentration levels from the primary and reference sensing devices; comparing the first oxygen concentration level and the second oxygen concentration level; and causing transmission of a gas leak to occur if a difference between the second oxygen concentration level and the first oxygen concentration level is greater than a threshold difference based on the comparison.

Further, according to some exemplary embodiments, the primary sensing device and the reference sensing device are located within the sensor assembly and exposed to the same environmental variable exposure.

Further, according to some exemplary embodiments, the gas detector further comprises a filter positioned on a side of the flue, wherein the filter is configured to screen out one or more gases from reaching the reference sensing device.

Further, according to some exemplary embodiments, the primary sensing device is adapted to be exposed to a potential leakage source and the reference sensing device is adapted to be exposed to an environment other than the potential leakage source under the same environmental variable.

Further, according to some exemplary embodiments, the threshold difference is based on between 5% and 10% of the volume of the oxygen concentration level. For this reason, the threshold difference is based on the flammability level of the gas. Further, the target gas is a refrigerant gas.

Further, according to some exemplary embodiments, the sensor assembly is further configured to receive one or more environmental variables and correct the first oxygen concentration level reading and the second oxygen concentration level reading based on the environmental variables. The control circuit includes at least one processor having computer-coded instructions therein, wherein the computer instructions are configured to cause operation of the sensor assembly by providing an alarm signal when executed. In this regard, the sensor assembly is a fully analog system or a digital system.

Furthermore, according to some exemplary embodiments, the flue is sized such that the mean free path of the gas being sensed is not obstructed. In this regard, the diameter of the flue is about 100 times the mean free path of one of the measured gas and ambient air. Furthermore, the response time of the sensing is adapted to remain within acceptable limits based on the length of the flue, wherein the length of the flue is about 0.1 to 3 meters. In some embodiments, the diameter of the flue is greater than 10mm.

Further, according to some exemplary embodiments, a method of determining a gas leak using a sensor assembly including a primary sensing apparatus and a reference sensing apparatus includes determining a first oxygen concentration level for a given zone via a flue extension coupled with the reference sensing apparatus and determining a second oxygen concentration level for the given zone via the primary sensing apparatus. A control circuit compares the determined first and second oxygen concentration levels and, based on the comparison, triggers an alarm or notification if the difference between the first and second oxygen concentration level readings is greater than a threshold difference.

Further, according to some exemplary embodiments, each of the primary and reference sensing devices is exposed to the same environmental variable, wherein the primary environmental variable comprises at least one of temperature, pressure, and humidity.

Further, according to some exemplary embodiments, the flue extension is configured to screen out one or more target gases from reaching the reference sensing device.

Further, according to some exemplary embodiments, the primary sensing device is adapted to be exposed to a potential leakage source and the reference sensing device is adapted to be exposed to an environment other than the potential leakage source under the same environmental variable. The diameter of the flue is about 100 times the mean free path of the one or more target gases.

Further, according to some exemplary embodiments, one or more environmental variables are received and the first oxygen concentration level reading and the second oxygen concentration level reading are corrected based on the environmental variables. The method is performed via at least one processor.

One advantage of using chimneys on the sensing sensor and/or the reference sensor is to allow the sensor to passively access gases from different parts of the HVAC system. This also means that the sensor can be located in less challenging environmental conditions. For example, areas where gas leaks may accumulate may be affected by harsh environments (such as large fluctuations in temperature and/or RH), and the sensor may be connected to these areas through a flue. The use of the described chimney allows the sensor to be installed in a more gentle region of consistent temperature. The sensor may also be isolated from where gas leaks may accumulate to provide an environment with a lower operating temperature. Isolating the sensor from harsh environments allows the sensor to provide more accurate performance, minimizing compensation and reference difficulties, thereby reducing false alarms and extending sensor life.

Various embodiments discussed herein allow for monitoring and detecting gas leaks during operation, such as in refrigeration units. While various embodiments discuss refrigeration units, the various embodiments discussed herein may also be used for other types of gas leaks using closed loop cycles, such as in HVAC applications and the like. The refrigeration unit includes a closed loop cooling/refrigerant coil containing a flammable refrigerant. A2L refrigerant is more commonly used in such refrigeration units due to its lower Global Warming Potential (GWP), and therefore regulations have been enacted in various countries to monitor leaks to avoid hazardous conditions during use. Although A2L refrigerants generally have low toxicity and only slight flammability, a large leak can still create a hazardous situation. Therefore, monitoring and detection of such leaks is essential for the refrigerant unit. Various embodiments of the present disclosure allow for a simple and effective leak monitoring system.

In some embodiments, certain ones of the operations described above may be modified or further amplified. Furthermore, in some embodiments, additional optional operations may also be included. The modifications, additions, or amplifications to the operations described above may be performed in any order and in any combination.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A heating, ventilation and air conditioning (HVAC), the HVAC comprising:

a sampling tube fluidly coupled to a first opening defined in a conduit, wherein the sampling tube is positioned outside of the conduit and extends along a direction of gravity;

a sensor assembly fluidly coupled to the sampling tube, the sensor assembly configured to receive one or more gases having a greater density than ambient air, wherein the sensor assembly is configured to sense the one or more gases to generate a signal.

2. The HVAC system of claim 1, wherein the sensor assembly includes a first opening configured to allow diffusion of one or more gases therethrough.

3. The HVAC system of claim 2, wherein the first opening includes a filter configured to screen out dust and moisture from the one or more gases reaching the sensor assembly.

4. The HVAC of claim 1, further comprising a washpipe comprising a first end and a second end, wherein the washpipe is fluidly coupled to the sensor assembly at the second end, wherein the washpipe is fluidly coupled to the conduit at the first end, and wherein the washpipe is configured to receive one or more gases comprising ambient air from a refrigeration unit.

5. The HVAC system of claim 4, wherein the second end is positioned downstream of the first opening.

6. The HVAC of claim 1, further comprising a drain fluidly coupled to the sensor assembly, the drain configured to allow one or more gases to flow out of the sensor assembly.

7. The HVAC system of claim 4, further comprising a blower disposed within a duct unit interior, the blower configured to be periodically activated so as to blow the ambient air into the washpipe.

8. A sensor assembly, the sensor assembly comprising:

a chamber fluidly coupled to a coupon, the chamber configured to receive one or more gases from the coupon, wherein the chamber comprises:

a second opening configured to allow the received one or more gases to flow out therethrough; and

a gas sensor disposed within the chamber, the gas sensor configured to sense the one or more gases to generate a signal.

9. The sensor assembly of claim 8, further comprising a flush tube fluidly coupled to the chamber, the flush tube configured to facilitate a flow of the ambient air to the chamber in order to evacuate the one or more gases from the chamber, wherein the flush tube evacuates the one or more gases from the chamber and the gas sensor when the flush tube is configured to receive the one or more gases including ambient air from a conduit.

10. The catheter unit of claim 7, comprising:

a conduit:

a first opening along a direction of gravity, the opening fluidly coupled to a sampling tube positioned outside of the conduit; and

a second opening complementary to the first opening and along a fluid flow direction, the second opening fluidly coupled to an irrigation tube positioned outside of the conduit.